Air-cooled surface condenser



Feb. ,8, 1938. o. HAPPEL 2,101,478

AIR-COOLED SURFACE CONDENSER Filed June 22, 1936 3 Sheets-Sheet 1 AIR-COOLED SURFACE CONDENSER Filed June 22, 1956 3 Sheets-Sheet 2 UffaHap/ce2 Feb. 8, 1938. Q HAPPEL 2,107,478

AIR- COOLED SURFACE CONDENSER Filed June 22, 1936 5 Sheets-Sheet 3Patented Feb. 8, 1938 UNITED STATES AIR-COOLED SURFACE CONDENSER OttoHappel, Bochum, Germany Application June 22,

1936, Serial No. 86,682

In Germany October 17, 1934 1 Claim.

The condensation of the exhaust steam of high-powered engines workingwith a high vacuum, especially steam turbines, has heretofore alwaysbeen effected by water cooled condensers,

5 the cooling water of which is generally re-cooled by a tower cooler,unless an unlimited supply of water is available. Tower coolers take upmore space than the engines themselves. and there is riskof dust fromthe surroundings getting into the circulating cooling water, so as tosettle in the condenser tubes, which necessitates frequent cleaning outof the condenser with consequent temporary closing down ofthe plant. The,deleterious gases in the air also pass into the cooling Water and havea detrimental action on the condenser tubes. This results in leakage,which not only affects the vacuum but may also deteriorate the water ofcondensation us boilers.

The main disadvantage of a cooling tower is that a certain amount offresh water must be added to replace the cooling water evaporated by theascending current of air, and the supply of this additional water isfrequently costly and diilicult, as it has to be softened before it canbe used.'

My invention provides apparatus enabling the exhaust steam of engines tobe condensed by means of a blast of dry air, in a surface condenser,thus dispensing withcooling water and with a-tower and the auxiliaryplant` associated therewith.

Surface condensers cooled by a positively propelled current o! air arewell known, and it` has been proposed to provide for instance a smallreciprocating steam engine with a condenser of this kind, wherein theblast of air is produced by a fan, vin some cases with a vacuum, butsuch condensersare only suitable for small engines working with a -lowvacuum. It has also been proposed to use air'cooled condensers onlocomotives, the condenser elements consisting of narrow ellipticalribbed tubes arranged in rows on both sides of the tender and cooled bya fan,

4,5 but attempts to produce a vacuum have not beenv successful in thisconnection. Attempts in the past to apply condensers of this kind toengines of high power, especially turbines, working with a high vacuum,have failed, the chief reason being the difficulty of providing thenecessary high vacuum. In the summer the temperature of the air used forcooling may be as high as 25 C. so that the mean difference between thetemperature .of the exhaust steam and that of the cooling air is comedfor feeding the (Cl. 257-36) y paratively small, and this. has led tothe belief in the past that an airrcooled condenser would have to be solarge, and the volume of air so' great as to render the plantuneoonomical.

I have established that this view is not correct and that thedifficulties envisaged can be overcome by adopting the construction nowto be described. According to the invention the condenser is built up ofrows of ribbed tubes of small cross section arranged in parallel, incombination with fans of large diameter designed to blow a large volumeof air at a very low pressure, not exceeding about 25 mm. water column,through ,the system of tubessaid rows of tubes together with the fansbeing arranged above a large suction chamber open at the sides. Thecondenser tubes may be small diameter tubes of circular cross section,but are preferably of elliptical cross sectioruas suchtubes combine themost favourableA heat exchange properties with a comparatively lowresistance to the current of cooling air. i

It has been proposed heretofore to use air cooled condensers havingelliptical ribbed tubes, for use with locomotives and also forstationary engines, with air and 'water as the cooling medium, and fanshave been used with such locomotive condensers, but the fans wereIdesigned to produce, an air current of much higher pressure thanliscontemplated with my invention. The use of low air pressures, whichpreferably may not exceed about 10 mm. water column, is an essentialfeature of the invention. Means are preferably provided for controllingthe speed of the fans. This enables the speed to be increased in summerwhen the temperature is comparatively high, and also at other times whenthe load is high, and the speed can be reduced in winter when thetemperature is lower.

The arrangement of the cooling elements and fans above a large opensided suction chamber results in a reduction of air velocity, so thatthe air current is fully utilized for cooling purposes, and the fansthemselves only have to work against low pressures. As regards the sizeof the suction chamber, the chamber may for example be approximately 6meters in height with a. 16,000 kw. turbo-generator.

The rows of ribbed tubes are preferably arranged in pairs, the two rowsconstituting a pair being arranged at right angles or preferably at anacute angle so that they enclose between them a 'space of the shape ofan equilateral triangle, above the apex of which is disposed the steampipe, and the fans being arranged at the base. Two or more such groupsmay be arranged side by side, according to requirements. This results incon' siderable saving of space as compared with a tower cooling plantand eliminates the other disadvantages associated with known plants forthis purpose.

In the above mentioned air cooler condensers for locomotives thecondenser tubes are in some cases arranged at an angle to each other sothat they enclose a triangular space, the base of which is formed by thefans, the tubes being at an ob- 'tuse angle to each other." The acuteangular arrangement according to my'invention has the advantage that theentrance area for air into the condenser. tube is substantially largerthan the delivery area of the fans, possibly twice as large, so'that theair velocity is reduced before entry among the tubes. Assuming that theair is discharged by the fans at a velocity of 8 to l0 meters per 'sec.,then its velocity on entry intov the condensers will have been reducedto approximately 4 to 5 meters per second. As compared with this thereduction of velocity in the case of locomotive condensers iscomparatively slight, owing to the obtuse angle formed by the condenserelements.

The acute angle arrangement also has the advantage that the base area isreduced.

The speed of the fans may be controlled in any convenient manner and thefans may be collectively or separately controlled. In the latter casemulti-phase current motors may be used to drive the fans, and the speedof these motors may be controlled from a central point, as for exampleby a frequency transformer, in accordance with the load or the outsidetemperature. The capacity of the fan motors is such that they are ableto sustain a load in' excess of normal, so that they are capable ofdeveloping the necessary power for the additional voliune of airrequired inthe summer when the temperature is higher.

An lexample ofv apparatus according .to the invention is showndiagrammatically in the accompanying drawings, applied to aturbo-generator of 16,000 kw.,and wherein Fig. 1 is a front elevation,

Fig. 2 a plan, with the condenser structure omitted in the lower halfthereof to show the ans,

Fig. 3 a side elevation, and Fig. 4 is a cross sec- ;iional view throughone of the tubevbanks of The exhaust steam from the turbine 2 whichdrives the generatori passes through the main distributing pipes 3 tothe several condenser elements 4. Y

The elements 4 consisting of one or more rows of tubes 20 are arrangedat an acute angle to each other as shown in Fig. 3, so that they enclosea triangular space above the vertex of which is the steam distributingpipe 3, and the base being formed by the fans 9. In the constructionshown by way of example the fans are 3 to 4 meters in diameter andrunning at approximately 300 revolutions per minute which propels theair against a pressure of about 10 mm. water column.

The elements 4 are provided with pipes I0 for the discharge of thecondensate, and with air pipes Il. The whole plant is shown installed inan annex I2 to the engine room i3, with the elements at the same levelas the turbo-generator, and the suction chamber i4 being below thislevel. Each fan may have a separate electric motor l5 as shown, themotors being preferably multiphase. All the motors may be controlled bycontrolling means common to them all, for example by a frequencytransformer controlled in turn by the output of the engine or by theexterior temperature or by the vacuum, so that the fans will run atspeeds to suit the existing conditions of operation.V

Fig. 4 illustrates by a cross sectional view on a line perpendicular toone of the tube banks 4 inv Fig; 3 the tube and 1in structure and therelation of adjacent tubes.

Ahigh vacuum surface condenser for stationary steam engines and turbinesoperating under high vacuum, comprising a foundation having a suctionchamber, a main distributing pipe in a. space above the chamber andthrough which the exhaust steam passes from the turbine, groups ofribbed tubes of which each tube is of small crosssection connected toand extending in pairs down from the distributing pipe to form an acuteangle,

and a plurality of fans arranged in a row under the tube elements todraw a large volume of air from the suction chamber up and around thetube elements.

OTTO HAPPE'L.

